Welcome Spring With Moist Lemon Poppy Seed Cupcakes

These crazy moist lemon poppy seed cupcakes are the prettiest, easiest, most delicious cupcakes you will ever make! Poppy seeds and lemon are a match made in heaven, the perfect cupcake flavor combination you must try!

Best lemon poppy seed cupcake recipe

These poppy seed and lemon cupcakes are fluffy, tender with incredible aromatic lemon flavor, packed with poppy seeds, filled with tangy lemon curd, and covered with an easy whipped mascarpone frosting. They're one of my favorite lemon desserts!

You won't need any fancy kit or ingredients, and the recipe comes together really easily. This recipe is perfect for beginner bakers, but everyone is always so impressed!

My lemon curd recipe that I use for the filling is incredibly creamy, tangy, and buttery. It's made with egg yolks for extra richness and fresh lemon juice for the best flavor. Finally, a beautiful whipped mascarpone frosting is added on top, which is perfectly balanced, light, and less sweet than traditional buttercream!

Katalin's Key take on how to make moist cupcakes

Baking is science, so using the right ingredients and techniques is essential to achieve the best results. And you all want super moist cupcakes, right?

These cupcakes will stay super moist and tender for days after baking. The secret tip (although I share it all the time) is to use a baking hack that gives them extra lift and lightness.

Before baking – mix a small amount of white vinegar with baking soda and fold it into the batter. I'll show you exactly how to use this hack below, but I promise it will make cupcakes airy and much lighter than any cupcakes you have baked before.

Ingredients

You will need some pantry basics to make this cupcake, like butter, flour, egg, milk, and sugar. The lemon curd also comes together easily using fresh lemon juice, sugar, and egg yolk. The frosting is made of only three ingredients: mascarpone, heavy cream, and powdered sugar. For a printable recipe card, visit the original lemon poppy seeds cupcake recipe at Spatula Desserts.

Start with the lemon curd filling

Zest both lemons using a microplane grater and set aside.

Juice the lemons into a heatproof bowl with the room-temperature egg yolk and sugar. Place this bowl over a saucepan of simmering water (not boiling), but do not let the bowl touch the water.

mixing lemon curd ingredients in a double boiler.

Cook the curd over medium-high heat in the double boiler while whisking constantly to avoid the egg scrambling. The curd will thicken to a custard consistency after 8-10 minutes, and if you have a thermometer, it will read 80C /176F.

Pour the cooked curd through a sieve to ensure no lumps, and then mix small chunks of softened butter one at a time with a rubber spatula. Make sure each butter chunk is fully incorporated before adding the next.

Fold in half of the grated lemon zest (the other half will go into the cupcake base) and pour the curd into a jar. Cover the surface with plastic wrap to prevent skin from forming and place it into the fridge, where it will continue to thicken as it cools.

Make the lemon poppy seed cupcake base

Preheat your oven to 175℃ / 350℉ (no fan) and line a cupcake tin with muffin liners.

Massage the remaining lemon zest into the white granulated sugar with your fingertips. This heightens the lemon flavor.

Use an electric hand whisk to cream the room-temperature butter and the lemon sugar together until light and fluffy. This will take a few minutes.

Add the room-temperature eggs one by one while the mixer is still running, and then add the vanilla extract.

Sift together the flour, baking powder, and salt (the dry ingredients). Never skip the salt; it balances sweetness and enhances the flavors!

Add the dry ingredients to the wet mixture in thirds, alternating with the room-temperature milk. Have the mixer on the low-speed setting for this stage, and stop as soon as the ingredients are incorporated to avoid overmixing. Finally, fold in the poppy seeds.

Mix vinegar with the baking soda, which will foam and bubble. Immediately fold this mixture into the lemon poppyseed cupcake batter.

Pipe or spoon the batter evenly into the prepared cupcake tin, filling each about ¾ full. Do not overfill, or they will mushroom!

Bake the cupcakes 175℃ / 350℉ for 20-22 minutes in the preheated oven. They are ready when an inserted toothpick comes out clean with no sticky batter. Do not overbake.

Allow the baked cupcakes to cool completely on a wire rack. Do not fill or frost while warm, as the filling and frosting can melt and go runny.

Assemble the cupcakes

Whip the high-fat mascarpone mascarpone, high-fat cold heavy cream, and sifted powdered sugar with an electric hand mixer for a minute or two just until it reaches a creamy, fluffy consistency.

Make a small hole in each cupcake with a spoon or knife and fill them with the lemon curd.

Pipe frosting onto each cupcake and decorate with more poppy seeds before serving. I also like to add edible flowers!

Storing and freezing

Store leftover lemon poppyseed cupcakes (if there are any) covered and refrigerated for 1-2 days. Bring them back to room temperature before serving so the frosting can soften slightly before you enjoy them.

You can freeze the lemon poppy seed cupcake base without filling or frosting. Wrap them in plastic food wrap to prevent freezer burn, and place them into a ziplock bag.

You can also freeze lemon curd, place it in an airtight container, and cover the surface with plastic food wrap.

I do not recommend freezing mascarpone frosting, as defrosting can affect the texture.

Flavor variations

Once you have mastered this easy lemon and poppyseed cupcake recipe, try to take it further with some options below.

Feel free to swap out the vanilla base for a delicious, moist chocolate base I use, e.g., in my hot chocolate cupcakes.

Try making a different citrus curd filling, e.g. using oranges instead. I also love to use my mango curd in cupcakes!

Alternatively, this recipe can be made by adding different spices, such as a pinch of ground cardamom, to the batter.

You can also try some of my other cupcake frostings with this recipe. I recommend my Swiss Meringue Buttercream, which you can also flavor with lemon zest, or a cream cheese frosting would be lovely, too.

Expert tips to make lemon poppyseed cupcakes

I recommend making the lemon curd first; it needs time to set in the fridge. Meanwhile, bake the cupcakes. Prepare the whipped mascarpone frosting once the poppy seed muffins and lemon curd filling are cooled.
Make sure you are using room temperature ingredients where specified. Always use room temperature eggs in baking and ensure the milk is not cold either. The unsalted butter for the lemon curd and cupcakes must also be softened at room temperature. This can mean taking it out of the fridge an hour ahead. Read my post on how to soften butter.
Don't overmix cupcake batter, or it can overproduce gluten, making the cupcakes tough. Stop as soon as the ingredients are incorporated.
The mascarpone and heavy cream should be high in fat and very cold for the frosting. Low-fat options contain too much water, resulting in runny frosting.
If you do not have mascarpone, feel free to replace it with full-fat cream cheese and make cream cheese frosting instead.
Never frost-warm cupcakes.
Applying a soaking syrup (like lemon syrup) to the cupcakes will also make them super moist and flavorful, although this is optional.
Make my macaron recipe with the leftover egg whites!

Try some of my other cupcake recipes

If you loved these cupcakes, you will also love some of my other fun and easy cupcake recipes:

Make sure to also check out this round-up of the best filled cupcake recipes for inspiration on what to bake next!